Tisch Environmental TE-5200, Operation Manual

Page: 14 / 34

TE-5200 14 Operations Manual
standard flows rather than actual flows and is taken from the Qstandard
section of the Orifice Calibration Certificate. The Qactual flows are used when
calibrating a PM-10 sampler.
The five orifice manometer readings taken during the calibration have been
recorded in the column on the data worksheet titled H
2
O (in). The five sampler
manometer readings taken during the calibration have been recorded under
the column titled FLOW (mano).
The orifice manometer readings need to be converted to the standard air flows
they represent using the following equation:
Qstd = 1/m[(Sqrt((H
2
O)(Pa/760)(298/Ta)))-b]
where:
Qstd = actual flow rate as indicated by the calibrator orifice, m
3
/min
H
2
O = orifice manometer reading during calibration, in. H
2
O
Ta = ambient temperature during calibration, K ( K = 273 +
o
C)
298 = standard temperature, a constant that never changes, K
Pa = ambient barometric pressure during calibration, mm Hg
760 = standard barometric pressure, a constant that never changes, mm Hg
m =
Qstandard slope of orifice calibration relationship
b = Qstandard intercept of orifice calibration relationship.
Once these standard flow rates have been determined for each of the five run
points, they are recorded in the column titled Qstd, and are represented in
cubic meters per minute.
The sampler manometer readings taken during the calibration need to be
corrected to the current meteorological conditions using the following
equation:
FLOW (corrected) = [Sqrt((H
2
O)(Pa/760)(298/Ta))]
where:
flow (corrected) = sampler manometer readings corrected to current Ta and Pa
H
2
O = sampler manometer readings during calibration
Pa = ambient barometric pressure during calibration, mm Hg.